Wind tunnel with an effective variable nozzle for testing various aerospace specific sensors and probes

ABSTRACT

An apparatus for a unique wind tunnel useable for testing various aerospace specific sensors and probes is presented. The wind tunnel apparatus as presented utilizes an effective variable nozzle and thus allows for the testing of such aerospace devices over a near infinite Mach and Reynolds numbers in subsonic flow. The variable nozzle allows for quick and easy adjustment over a minimum 1×10̂7 range of Reynolds number conditions from flow velocity of Mach 0.01 to 0.99. The optimal design of the wind tunnel also allows for adaptation to different size test tunnels, using existing facilities to reduce cost, thus enabling various aerospace design applications. The apparatus of the present invention, the variable nozzle test wind tunnel, provides a highly variable test environment in order to improve the development of advanced aerospace sensors, including benefits such as: development of flow sensors to prevent compressor stall; development of optical sensors to optimize turbine and compressor airflow; and, development of temperature sensors to increase efficiency of turbine engine operation.

CROSS REFERENCE TO PRIOR APPLICATION

This patent application claims the benefit of U.S. Provisional Application No. 62/423,816 filed on Nov. 18, 2016. The above provisional application is incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The present invention relates to an apparatus for a wind tunnel with an effective variable nozzle for testing of various aerospace specific sensors and probes, and, more particularly, to a variable nozzle for a wind tunnel device that allows for valid and effective aerospace testing at differing pressures, air flow rates and temperatures, even at subsonic speeds.

BACKGROUND OF THE INVENTION

[to be completed pending amendment].

SUMMARY OF THE INVENTION

The present invention is directed to providing a wind tunnel with an effective variable nozzle that allows for: sustaining necessary pressure for required velocity of Mach <=1.00; operation at low pressures and a high flow rate; operation at high pressures and a low flow rate; vary temperature from ambient to a minimum of 700 degrees Kelvin; controlling and maintaining the set temperature and pressure settings; producing valid results based on initial calibration; and, an ability to maintain subsonic flow and still obtain desired Reynolds numbers, which further requires: and ability to control and maintain air density, which can be accomplished by controlling temperature and pressure settings, and control and maintain set air flow velocity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a picture of the wind tunnel device, according to an embodiment of the present invention.

FIG. 2 illustrates a cutaway of the completed wind tunnel device showing the cone inserted 5″, according to an embodiment of the present invention.

FIG. 3 illustrates a cutaway of the completed wind tunnel device accenting the connecting bolts and the machine polished finish of the cone itself, according to an embodiment of the present invention.

FIG. 4 illustrates a cutaway of the completed wind tunnel device accenting flanges and the measurement device probe to the end of the cone, according to an embodiment of the present invention.

FIG. 5 illustrates the assembly details of the wind tunnel device, according to an embodiment of the present invention.

FIG. 6 illustrates a simulated flow of the wind tunnel device at Mach 0.9, ½ total device insertion distance, according to an embodiment of the present invention.

FIG. 7 illustrates a simulated flow of the wind tunnel device at Mach 0.9, ⅕ total cone insertion distance, according to an embodiment of the present invention.

FIG. 8 illustrates a simulated flow of the wind tunnel device at Mach 0.9 with cone fully out of test tunnel, according to an embodiment of the present invention.

FIG. 9 illustrates how the final device connects to the Hot Jet Test Rig, according to an embodiment of the present invention.

FIGS. 10-19 illustrate engineering schematics of the wind tunnel device, according to an embodiment of the present invention.

FIGS. 20-44 illustrate presentation slides of various aspects of the wind tunnel device, according to an embodiment of the present invention.

DETAILED DESCRIPTION

Referring to FIGS. 1 through 5, it is clear to see the primary components of the wind tunnel device 100.

Referring specifically now to FIGS. 1 and 2, the cone/nozzle 101 is constructed of 304 Stainless Steel, connected and locked onto a course threaded adjustment rod 102, that is supported by a stainless end flange with a thickness that allows for minimal movement along the y and z axis through its x axis insertion distance.

The test tunnel portion is connected to the adjustable device and the adapter flange to the Hot Jet Test Rig via Stainless Steel adapter flanges, welded to each end of the test tunnel, also made of 304 Stainless Steel. 4 NPT ports are tapped around the circumference of the test tunnel near the entrance to reduce possible turbulence in that region caused by the cone insertion distance for more accurate test probe measurements. The adjustable device housing is currently designed with 6061-T6 anodize aluminum, though if the convection temperature at the higher ranges may require this to be constructed of 304 Stainless Steel as well. Aluminum lightens the device significantly, and would be recommended unless an additional support can be added under the device. The measurement device is made partially of an off the shelf height caliper, though the base is customized to attach to the end flange, and the measurement probe is designed to reach the end of the cone to make the cone insertion distance simple and easy to measure. The detail drawings for all of the components of the final device design can be found in the engineering schematics (which will be described in detail below).

SolidWorks was used to create flow models, showing the approximate flow velocity during a variety of conditions to ensure steady flow through the test tunnel and into ambient air through the exhaust ports designed in the variable device housing and the end flange.

Referring now to FIG. 6, this figure illustrates the simulated flow through the device at 45 psig test tunnel pressure, 294 Kelvin tunnel temperature, and Mach 0.9. The flow diagram describes flow velocity from low to high by varying the colors from light blue to red respectively. With the cone at ½ of total insertion distance, it shows steady flow in the test tunnel for improved test probe accuracy, and a sharp increase as expected at the cone/tunnel interface just as you would expect with a nozzle. The flow then dissipates desirably into the ambient air.

Referring now to FIG. 7, this figure illustrates the simulated flow just as the previous diagram through the device at 45 psig test tunnel pressure, 294 Kelvin tunnel temperature, and Mach 0.9. The flow diagram describes flow velocity from low to high by varying the colors from light blue to red respectively. With the cone at ⅕ of total insertion distance, it still shows steady flow in the test tunnel though with higher velocities beginning shortly after the test ports. However, with the cone further out of the test tunnel, similar to a larger diameter nozzle, the velocity increase at the exit is not as high. The flow still dissipates desirably into the ambient air.

Referring now to FIG. 8, this figure illustrates the simulated flow just as the previous diagram through the device at 45 psig test tunnel pressure, 294 Kelvin tunnel temperature, and Mach 0.9. The flow diagram describes flow velocity from low to high by varying the colors from light blue to red respectively. However, with the cone completely out of the tunnel, essentially removing the nozzle, the test tunnel velocity rises sharply past the test tunnel ports. The velocity slows at the exit, though still has higher velocities inside the device housing than in the previous examples. Though it is not definitive, boundary layer issues may play a part in this. Also, though the cone setting mimics a “no-nozzle” condition, the bulk of the cone assembly is still in the direct exit airflow. The data also shows unpredictable data when the cone is at the fully out state. However, the device was not designed for this condition, and all other cone insertion distances have a steadier flow at all points through the device.

Referring now to FIG. 9, this figure illustrates how the final variable Reynolds and Mach number Device attaches to the existing Hot Jet Test Rig, and simulates the flow continuing through the entirety of the system, including the initial jets, air flow heater, honeycomb flow straightening screens, and the impinging jets for controlling pressure. The Reynolds number is defined as a dimensionless quantity expressing the ratio between a moving fluid's momentum and its viscosity. The design of the nozzle apparatus allows for the control of variable Reynolds Number, while keeping the test tunnel Mach constant. This is especially valuable for aerospace applications, as there are many conditions, especially within the engines where density and flow conditions vary widely, and Mach number is not an effective predictor of the engine behavior.

Referring now to FIGS. 10-19, . . . [to be completed pending amendment].

Referring now specifically to FIG. 17, the design of the adjustment rod 102 of the present invention according to a preferred embodiment is shown in detail. The overall length of the adjustment rod 102 is 17.50 inches, with a chamfer lead in/out edge [insert reference #] measuring 1.50 inches in length. The chamfer lead in/out [insert reference #] allows for good thread starts when connected to the cone/nozzle 101. The overall diameter of the adjustment rod 102 is 1.25 inches. [to be completed pending amendment].

Referring now specifically to FIG. 18, the design of the cone/nozzle 101 of the present invention according to a preferred embodiment is shown in detail. The length of the cone/nozzle 101 is 10.00 inches, while the diameter of the cone/nozzle 101 is 2.00 inches at its widest end, with a cone shape according to the equation: y=(x/10)^(0.7). A cutout [insert reference #] is provided for insertion/receiving of the adjustment rod 102. Preferably, the adjustment rod is threaded. [to be completed pending amendment].

The variable nozzle design allows for full control of a completed cone design and is easily adaptable for connection to existing wind tunnel test devices (such as a Hot Jet Test Rig). The design also allows: for probe sensor testing in a test tunnel of an appropriate size for the cone design, for the airflow from the test tunnel to escape into ambient with the least impediment to reduce turbulence, for simple and accurate adjustment of the cone location, and for simple and accurate measurement of the cone insertion distance.

It is to be understood, of course, the variable nozzle apparatus can be scaled for larger wide tunnels due to the adaptable design, and would require only minor modification to also test hypersonic and supersonic conditions. Such modifications are to be considered as within the scope of the present invention. Additionally, and as such, manufacturing and assembly of the device are simplified even if device changes are required.

Referring now to FIGS. 20-44, . . . [to be completed pending amendment (if not incorporated above)].

In the foregoing description, the apparatus of the present invention have been described with reference to specific examples. It is to be understood and expected that variations in the principles of the apparatus herein disclosed may be made by one skilled in the art and it is intended that such modifications, changes, and substitutions are to be included within the scope of the present invention as set forth in the appended claims. The specification and the drawings are accordingly to be regarded in an illustrative rather than in a restrictive sense. 

What is claimed is:
 1. An apparatus for controlling the subsonic air flow of a wind tunnel, the apparatus comprising: a variable air heater; a pressure release value system; and a variable nozzle, comprising: an inverse cone assembly, wherein the apparatus allows for continuously adjustable Reynolds Number or Mach Number defined subsonic air flow parameter.
 2. The apparatus according to claim 1, wherein the variable air heater allows for a static setting of a temperature.
 3. The apparatus according to claim 1, wherein the pressure release valve system allows for a static setting of an air pressure.
 4. The apparatus according to claim 1, wherein the inverse cone assembly of the nozzle allows for a precise set of an air flow exit area.
 5. The apparatus according to claim 1, wherein the variable nozzle is constructed of stainless steel.
 6. The apparatus according to claim 1, wherein the inverse cone assembly comprises: an adjustment rod; a cone, that is connected and locked onto the adjustment rod, wherein the cone and the rod are supported by a stainless end flange with a thickness that allows for minimal movement along the y and z axis through its x axis insertion distance.
 7. The apparatus according to claim 6, wherein the inverse cone assembly is 10 inches in length and the cone is 2 inches in diameter at its widest end.
 8. The apparatus according to claim 6, wherein a shape of the cone is defined according to the equation y=(x/10)^(0.7).
 9. The apparatus according to claim 6, the cone further comprises a cutout portion designed to allow for threaded receiving of the adjustment rod.
 10. The apparatus according to claim 6, wherein the adjustment rod is 17.50 inches in overall length and 1.25 inches in overall diameter.
 11. The apparatus according to claim 6, the adjustment rod further comprises a chamfer lead in/out edge measuring 1.50 inches in length. 